DTSC has determined that the material left over after valuable metals have been removed from the material produced by the shredder does NOT pose a risk to human health or the environment. This material is called treated metal shredder residue (MSR) and is classified by DTSC as nonhazardous waste.
The small amount of remaining metal that is contained in the treated MSR is chemically bound in the residue, greatly reducing its ability to leach into the environment.
For more than 30 years, treated MSR has been allowed by DTSC and other regulators to be used in municipal landfills as daily cover. After decades of use, no releases to groundwater have ever been detected, even in unlined landfills. Additionally, air monitoring devices placed on landfill equipment show no hazardous air emissions.